Effects of conventional ultrafiltration on renal performance during adult cardiopulmonary bypass procedures

Ultrafiltration has been used successfully in a variety of applications in the perioperative setting to assist in hemoconcentration and volume reduction. This study was designed to investigate the effects of aggressive conventional hemofiltration on bypass urine production, fluid balance, and renal performance in the 24 hours after bypass procedures in the adult population. A prospective, randomized study was designed to determine the effects of conventional ultrafiltration (CUF) during bypass while monitoring urine dynamics intraoperatively and in the 24-hour post-bypass period. Study group 1 (CUF, n = 49) was compared to control group 2 (non-CUF, n = 47) by monitoring urine values, volume additions, and packed red cell (PRC) use throughout the procedure. The mean total CUF volume removed from group 1 was 5781 +/- 2612. There were no differences in pre-bypass, total bypass, or total operating room (OR) urine between the two groups. The 24-hour urine totals were significantly higher in group 2 (2389 +/- 895) than in group 1 (2035 +/- 895). The ending bypass hematocrit was also lower in group 2 (26 +/- 2.0) than in group 1 (30 +/- 6.0). OR PRC additions were higher in group 2 (395 +/- 699) than group 1 (204 +/- 300). The non-CUF control group 2 experienced significantly greater ending fluid balance (3006 +/- 868) compared with group 1 (744 +/- 1271). No significant differences in pre- or postoperative creatinine values were observed. Aggressive CUF can be safely used during cardiopulmonary bypass in the adult population to reduce fluid accumulation and elevate bypass hematocrit without effecting bypass or intraoperative urine production.